Depression may have a bodily cause - scientists

But a new study from the University of Bristol suggests this view should be reconsidered. Researchers have found that depression, schizophrenia, bipolar disorder and even Alzheimer's disease may be linked to abnormalities in the immune system.

In other words, the mind and body are one system, and inflammation in the body can have an impact on our mental health.

The study is published in the journal Molecular Psychiatry.

Details: Christina Dardani et al, Immunological drivers and potential novel drug targets for major psychiatric, neurodevelopmental, and neurodegenerative conditions, Molecular Psychiatry (2025). DOI: 10.1038/s41380-025-03032-x

What exactly was discovered?

The scientists studied 735 immune proteins that can be measured in human blood and matched them to seven common neuropsychiatric diagnoses: depression, anxiety, schizophrenia, bipolar disorder, Alzheimer's disease, autism, and ADHD.

As a result, they identified 29 proteins that likely play a causal role in these diseases. Of these, 20 are already being used as targets in therapies for other conditions, which means - we already have drugs that could potentially be adapted to treat mental disorders.

Why it matters

Today, most patients with depression or schizophrenia are treated with drugs that act on serotonin and dopamine - the main 'happy chemicals' in the brain. But statistically, one in three of these drugs don't work.

This is forcing scientists to look for other explanations and mechanisms. A new study shows: inflammation - a systemic and brain immune response - may be part of the cause.

As Professor Ghulam Khandaker, one of the paper's authors, puts it:

"We have shown that inflammation in the body and brain can influence the risk of psychiatric disorders. This changes the very understanding of these conditions - we should now see them as diseases of the whole body, not just the brain."

What's next?

The researchers are going to test the findings using other methods: analysing medical records, animal experiments and human clinical trials. This will help figure out

• exactly how inflammation causes psychiatric symptoms,

• whether they can be treated by targeting the immune system,

• which drugs are already suitable and which need to be developed from scratch.

If the hypothesis is confirmed, a revolution in the treatment of depression and schizophrenia could await us - the approach will become more precise and the therapies more effective.